Scientific Intelligence. Geology. 401 



ment of the artery is a one, though complex, phenomenon, a 

 movement which results from all those which are derived from 

 its elasticity, and more particularly from its dilatation, its lo- 

 comotion and elongation. As to the strength or impulse of 

 the artery, it depends either on the dilatation alone, or on the 

 dilatation complicated with the effort of the blood against the 

 parietes of the vessel which are at the time depressed by the 

 finger which is imposed on it. According to Galen and Har- 

 vey, the pulse, that is to say the stroke which is felt by the 

 finger which is applied to the artery which beats, is the shock 

 produced by the dilated parietes of the artery. According to 

 Weibrecht, the pulse is the result of the shock produced by the 

 whole displaced artery, and not solely by the dilatation of its 

 parietes. And, according to Arthaud, who denies there is any 

 dilatation, and who nevertheless discovers the pulse in the arte- 

 ries themselves, which, according to him, have no locomotion, 

 the pulse is the simple effect of the impetus of the blood against 

 the parietes of the artery, which is at the moment depressed by 

 the effort of the finger. After all that has been said, it will be 

 seen, that in those arteries whose course is straight, and whose 

 locomotion is but small, the pulse is produced chiefly by the di- 

 latation ; that in arteries which are tortuous, and whose loco- 

 motion is great, the pulse is produced chiefly by that locomo- 

 tion ; and, finally, that when the finger does not merely touch 

 the artery, or rather is merely touched by it, but presses upon 

 and depresses it, the pulse is chiefly owing to the impetus of the 

 blood in its parietes. Upon the whole, the pulse is nothing 

 more than the beat felt by the finger ; and is composed of all 

 the elements, and all the circumstances which compose or in- 

 fluence, or complicate that beat. 



GEOLOGY AND MINERALOGY. 



18. Reduction of Silver, Lead, and Copper. M. Becquerel, 

 on presenting some electro-chemical apparatus to the Academic 

 Royale des Sciences of Paris, by the aid of which he had been 

 able to effect the immediate reduction of silver, lead, and cop- 

 per, staled that, without the interventlbn of mercury, by con- 

 structing an electro-chemical apparatus with iron, a saturated 

 solution of common salt, and an ore of silver, properly prepared, 



